In an ideal situation, a transmitter may transmit information over a channel or medium and the transmitted information may be received without alteration and processed by a receiver. However, a transmission medium or channel is constantly subjected to impairments such as noise and interference. Consequently, when a transmitter transmits information, a receiver may not receive the information in an identical manner in which it was transmitted. This may be due to impairments in a channel that may typically introduce errors in the transmitted information. A transmitter may code the data in such a manner that error introduced during transmission may be detected and/or corrected during reception.
Cyclic redundancy is one method, which may be utilized to code information for transmission so that at least some errors may be detected and/or corrected. A cyclic redundancy check (CRC) may be computed for a group or block of bits referred to as frames. The computed CRC may then be appended to each frame for which a CRC is computed and the frame with the CRC may be transmitted. The appended CRC may be referred to as a frame check sequence (FCS).
On the receive side, the frame check sequence may be extracted from the received information and a CRC may be computed for the received information. This calculated CRC of the received frame may then be compared with the frame check sequence and if there is a mismatch, then the received frame may be in error.
CRC utilizes very little overhead and may be easily implemented. Many conventional devices currently use cyclic redundancy check (CRC) to determine if there is an error in information that has been received from a transmitting entity. For example, a receiver may be adapted to determine a CRC on frames in a payload of a received packet. The computed CRC may be compared with a frame check sequence to determine whether the frame is in error. If the frame is determined to be in error and the error may be corrected, then the frame may be acknowledged. If the frame is in error and the error may not be corrected, then the receiver may send an indication or a signal such as a negative acknowledgement, thereby causing the packet to be retransmitted by the transmitter.
In certain instances, for example, when a very large file is transmitted and received for processing, there may be a possibility that when a CRC is computed on a corresponding received frame, the computed CRC may pass even though there may be multiple bit errors in the receive frame. This may be referred to as a false CRC pass. These types of false CRC pass indicators may be destructive in a large program or image that is being transferred.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.